Treatment of clay



Patented ar. 13, 1923.

WILLIAM FELDENHEHEER AND WALTER WILLIAM PLOWMAN, OF LONDON, ENGLAND.

TREAT OF' CLAY.

No Drawing.

To all whom it may concern:

Be it known that we, WILLIAM FELDEN- IIEIMER and WALTER WILLIAM PnowMAN,

both subjects of the King of England, and both residing at London, England, have invented certain new and useful Improvements in the Treatment of Clay, of which the following is a specification.

This invention is for improvements in and relating to the treatment of clay.

It is known to purify clay b suspending it in a liquid medium by ai of a peptizing agent, and after subsidence of the impurities to separate the purified clay substance, for example, by addition to the suspension of a suitable precipitant. The deflpcculato'rs hitherto commonl used will. not, however, operate success ully with a number of clays, and in the case of others the difference between the minimum, and maximum concentration of the deflocculator which will maintain the clay in proper suspension is too small for satisfactory working on the commercial scale.

It has now been found that by the use of a peptizing agent of the type hereinafter described, certain clays which are not amenable to treatment by the deflocculators commonly employed, or which demand comparatively close adjustment of the concentration of these reagents, can be successfully treated so as to be maintained sufliciently long in suspension to enable the clay substance to be satisfactorily separated from the impurities and recovered on the industrial scale.

According to this invention, a process for the treatment of clay in which the clay substance is deflocculated in a. fluid medium, is characterized by efiecting the deflocculation with the aid of an-alkali resinate, or the equivalent thereof, for example, a resin acid in conjunction with an alkali or alkali salt which, with the acid, yields a watersoluble derivative. The term alkali resinate as used in this specification and claims includes such equivalents. I

The preferred defloceulating reagent is a solution of ordinary rosin in causti alkali, alkali silicate or carbonate.

The deflocculated clay may be recovered from its suspension in any known way.

The following are examples of deflocculating reagents according to this invention:

(A) 2 lbs. of commercial rosin are dis- Application filed November 5 1921. Serial No. 518,116.

solved in a solution of 2 lbs. of caustic soda (98 per cent) in 140 lbs. of Water at about 100120 F.

I (B) 1 lb. of commercial rosin is dissolved m 4 lbs. of sodium silicate (140 Twaddell) in 140lbs. of water.

These examples are given for illustrative purposes onlyand not by way of limitation, and it will be appreciated that the composition of the reagent utilized may be varied according to the nature of the cla to be treated, for, as previously indicate a given defiocculator is not necessarily applicable with success to all clays; in fact it appears doubtful if any reagent can be asserted to be a deflocculator for clays in general. For example, we have found that the majority of clays from N. Carolina, Georgia and Florida may be successively suspended by aid of rosin dissolved in caustic alkali, suitable relative proportions being 6 lbs. of rosin and caustic soda (equal parts by weight of each) per ton of clay in 20 tons of soft water. As illustrative-of the variation in the limit of concentration of this reagent, it may be mentioned that five times the quantity of the latter, namely 30 lbs. of rosin and caustic alkali (equal parts of each by weight) will successfully deflocculate the same weight of clay and water. For some individual clays, lower limits than these may be employed.

Clay from Gonnemaris (Cornwall), a clay presenting disadvantages in treatment by the known alkaline deflocculators, is another example of a clay which may be successfully brought into suspension by aid of rosin in caustic alkali.

On the other hand, some china clay from St. Remi, dAmherst, Canada, cannot be satisfactorily treated with rosin in solution in caustic alkali. In. this case, the solution of rosin in sodium silicate may be employed. For example, 750 lbs. of the clay in 15000 lbs. of soft water may be successfully brought into suspension by addition of 140 lbs. of solution (B) above. The same weight of clay and water can be equally efl'ectively treated if the concentration of the deflocculating reagent be five times that given, namely 5 lbs. of rosin and 20 lbs. of sodium silicate.

It not infrequently happens in aclay mine that the nature of the clayvaries in different parts of the'bed. In such a case, it

may be of advantage to use a mixture of the rosin dissolved in caustic alkali and the I rosin dissolved in the alkali silicate, or someoratory trial.

In carrying the invention into eil'ect in one way, the clay is washed by passin it over mica-drags in the usual manner, at instead of using water alone, a solution of rosin as above described is employed, of

the appropriate composition and concentra-- tion demanded for the clay under treatment. A greater quantity of mica is deposited on the drags than is the case when water alone is employed, and the clay dispersion is then passed on to a settling-tank where it is left long enough for further deposition of mica. From this tank the liquid carrying the clay in suspension is run into a depositing tank, in which the clay may be precipitated by the addition of any suitable precipitating agent, or otherwise recovered.

When precipitation is adopted, it is preferred to effect this in the manner described in U. S. Patent to Feldenheimer No. 1,23%,958, of December 16, 1919.

There results from this treatment a very finely divided and highly purified clay adaptable to a variety of technical applications.

The rosin solution may be added at any desired stage, e. g. prior or subsequently! to passing the suspension over the micadrags.

If desired, the rosin solution may be added to the suspension prior to entry into the tank after the clay has been treated in the customary manner b passing over mica-drags, and after bemg left to stand in the tank for a sufiicient period of time, the suspension may be then run into a second tank where the flbcculator is added.

Obviously, the invention may be applied not only for purification, but also for the deflocculation for various purposes of an already purified .clayl.

We claim mamas tion of a resin in an alkaline solvent therefor.

2. In the treatment of clay, the step consisting in eilfeeting defloceu'lation of the clay by admixing the latter with an aqueous solution of rosin in an alkaline holvent therefor.-

3. In the treatment of clay, the step consisting in effecting deflocculaltion of the clay by admixing the latter with a solution of rosin dissolved in an aqueous solution of an alkaline silicate.

4. In the treatment of clay, the steps consisting in efi'ecting deflocculation of the clay by admixing the latter with an aqueous solution of rosin in an alkaline solvent therefor, separating the suspension of clay substance from undeflocculated material, and recovering the clay from its suspension.

5. In the treatment of clay, the steps consisting in effecting deflocculation of the clay by admixing the latter with an aqueous solutron of rosin in an alkaline solvent therefor, allowing undetloeculated material to separate by subsidence, separating the suspension of clay substance from the deposit, and recovering the clay from its suspension.

6. In the treatment of clay, the steps consisting in edecting deflocculation of the clay by admixing the latter with an aqueous solution of rosin in an alkalinesolvent therefor, separating the suspension of clay! substance trom undeflocculated material, and precipitating the clay from its suspension y addition thereto of a flocculating reagent.

7. In the treatment of clay, the step consisting in admixing the clay with an aqueous solution of rosin in an alkaline solvent therefor in the proportion of substantially 3-15 lbs. of resin per ton of clay.

8. In the treatment of clay, the steps con sisting in preparing a substantially 5 per cent mixture of the clay with soft Water, and incorporating with this mixture rosin and an alkaline solvent therefor in the proportion of substantially 3 to 15 lbs. of rosin per ton of clay.

9. In the treatment of clay, the steps consisting in preparing a substantially 5 per cent mixture of the clay with soft water, incorporating with this mixture rosin and an alkaline solvent therefor in the proportion of substantially 3-15 lbs. of resin per ton of clay, allowing the mixture to stand, separating the suspension of clay substance from undeflocculated material, and separating the clay-substance from its suspension.

In testimony whereof We have signed our names to this specification.

1. In the treatment of clay, the step consisting in efiectin'g deflocculation of the clay by admiring the latter with an equeous soln= WILLIAM FIELIDENIIEIMER. WALTER WILLIAM PLOWMAN.

not 

